The present invention relates to printers, such as serial-type line printers, word processors, typewriters, etc., which are provided with a print element, e.g., a matrix-type print head, traveling along a print line of a platen, and execute a printing operation by means of a print ribbon stretched along the print line.
The printers of this type are generally constructed so that a ribbon cassette or cartridge as a ribbon supply means containing a print ribbon is mounted on a printer frame, the ribbon is partially exposed from the cassette to the outside, and the exposed ribbon portion is stretched so as to cover the whole printing range or stroke of a print element along a print line.
These prior art printers are disclosed in, for example, U.S. Pat. Nos. 4,203,676 and 4,352,575 and Japanese Utility Model Disclosures Nos. 54-72111, 57-101046, 57-57954 and 58-96976.
As means for stretching the print ribbon over the whole printing range, a mechanism is shown in, e.g., FIG. 8 of the Japanese Utility Model Disclosure No. 57-101046 which is designed so that a looped ribbon portion exposed to the outside is passed around a ribbon guide member which is provided with a guide roller mounted on the frame. In this case, the ribbon cassette is located in a fixed position on one end side of the printing range, while the ribbon guide member is positioned beyond the other end of the printing range. After mounting the cassette on the frame, the operator manually draws out the exposed ribbon portion and passes it around the ribbon guide member, thereby stretching the ribbon in place.
With the above described arrangement, however, the ribbon stretching work requires a very troublesome manual operation, inevitably soiling the operator's hands. Also, the exposed ribbon portion must be drawn out considerably long by manual operation. Unless the ribbon is carefully handled while it is being stretched, therefore, it may possibly be twisted or wrinkled, constituting a hindrance to ribbon feed during printing.
Disclosed in the Japanese Utility Model Disclosures Nos. 54-72111, 57-57954 and 58-96976, on the other hand, are printers in which the ribbon cassette is long from side to side so that the ribbon portion stretched between two ribbon exposing ends at both sides of the cassette can cover the printing range as it is.
In this arrangement, however, the cassette is increased in size, requiring a wider mounting space and limiting the spaces for other components of the printer. This is undesirable in view of the printer design, especially of the miniaturization of the printer.
As shown in FIGS. 3 to 6 of the Japanese Utility Model Disclosure No. 57-101046, for example, the printer may be provided with an arm member which can be slidably or pivotally drawn out from a compact cassette, and which is adapted to be extended so that the ribbon is stretched long when the cassette is set in place. Disclosed in the U.S. Pat. No. 4,203,676, moreover, is a printer in which the ribbon is arranged along the platen by means of a pair of flexible leaders and bridge means connecting the same. In the former arrangement, however, the cassette is complicated in construction, while in the latter the construction of the ribbon guide member is complicated, increasing the manufacturing cost. Likewise, in a printer disclosed in the U.S. Pat. No. 4,352,575, the cartridge is provided with a slidable adapter and is therefore complicated in construction, leading to an increase in cost.
Among the conventional examples described above, in particular, those printers using cassettes or cartridges of a special construction are undesirable. The reason is that, being disposable goods, the cassettes or cartridges for printers will be uneconomical and unfit for practical use if they are increased in unit cost due to their special construction.